| (19) |
 |
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(11) |
EP 0 416 722 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
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09.09.1992 Bulletin 1992/37 |
| (43) |
Date of publication A2: |
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13.03.1991 Bulletin 1991/11 |
| (22) |
Date of filing: 06.07.1990 |
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| (84) |
Designated Contracting States: |
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AT BE CH DE DK ES FR GB GR IT LI LU NL SE |
| (30) |
Priority: |
08.07.1989 GB 8915716
|
| (71) |
Applicant: PITMAN-MOORE LIMITED |
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Uxbridge
Middlesex UB9 6LS (GB) |
|
| (72) |
Inventor: |
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- Baker, Rodney Cyril
Berkhamsted,
Hertfordshire (GB)
|
| (74) |
Representative: Matthews, Derek Peter et al |
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Frank B. Dehn & Co.
Imperial House
15-19 Kingsway
London WC2B 6UZ
London WC2B 6UZ (GB) |
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| |
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|
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Remarks: |
|
The title of the invention has been amended (Guidelines for Examination in the EPO,
A-III, 7.3). |
|
| (54) |
Pharmaceutical compositions having differential drug release rate |
(57) A solid pharmaceutical composition for release of a biologically active substance
into a desired aqueous environment, containing a core and an outer layer, said core
comprising between 17 and 93% by weight of the biologically active substance, between
0.01 and 7% by weight of a water swellable polymer material and between 0 and 83%
of one or more accessory ingredients, relative to the total weight of the core; and
the outer layer comprising between 25 and 75% by weight of the biologically active
substance, between 25 and 75% by weight of a material for enabling rapid dispersion
of the outer layer into the aqueous environment and 0 to 50% by weight of one or more
accessory ingredients, relative to the total weight of the outer layer. The composition
is preferably formulated as a bolus for veterinary use.